The NABRE, in its footnote to this verse, states that the other to whom Jesus refers as testifying on His behalf is “likely the Father,” and go on to cite the upcoming verses concerning the four ways the Father testifies: (1) the testimonies of John, (2) the works Jesus does of His Father, (3) the belief of those who believe in the Father, and (4) Scripture. [Jn 5:33–34, 36, 37–38, 39–40 respectively]. As I come to those verses, I will examine each of those in turn.
Here I just stop and consider Jesus knowledge that the Father testifies on [His] behalf, and [Jesus knows] that the testimony he gives on [Jesus’] behalf is true.
Thomas, in the Summa III, discusses the four types of knowledge Jesus possessed: Divine as God, Beatific as the true Man eternally in the sight of God, infused knowledge from the Divine intellect into the human intellect, and acquired, the learning aspect of the true human brain. [1,14; 10; 11; 12 respectively] Understanding precisely how Jesus knew that the Father testified on his behalf is, to be honest, a mystery. Not only do I not understand precisely how I as a human being know what I know, which has consumed men epistemologically and scientifically for centuries. Here, in addition, we are faced with the mysteries of God, of the Trinity, of the Word, of the Incarnation. This is not just a seashore over-my-head reality but deeper than the deepest trench in the ocean out of my depth.
Now we can in awe watch as He grew [in] wisdom and age and favor before God and man. [Lk 2:52] We know that, even at the age of 12, He knew God was His Father. [Lk 2:49] So exactly how Divine knowledge and the Beatific Vision get translated into both infused human knowledge and where infused stops and acquired takes over….are grist for years of speculation and consideration. Suffice it to say that, at this juncture in his life, (a) He was absolutely aware of God; (b) He was absolutely aware He was the Father’s Son; (c) He was absolutely aware of His mission, of why His Father had sent him to earth [Jn 3:16]; (d) He had complete control of His Divine and human powers; (e) He had complete confidence in the Father; and (f) He wanted, sought, strived for, was complete absorbed in accomplishing His mission: “I have come to set the earth on fire, and how I wish it were already blazing! There is a baptism with which I must be baptized, and how great is my anguish until it is accomplished! [Lk 12:49-50]
Having alluded to, not proved, defined or even fully explored that infinitesimally minute portion of Jesus knowledge that we are able to speculate about, let alone the presence of and work of the Father and His relationship to the Father, let us leave that in awe and wonder and reverence and move on to the question of testimony. Having said that Jesus knew the Father, we now examine how and what He know about the Father’s testimony concerning Himself.
We certainly know that the Father inspired many through the Spirit to testify to His relation to Jesus. Gabriel describes the Father’s relation to Jesus in his Annunciation dialogue: The holy Spirit will come upon you, and the power of the Most High will overshadow you. Therefore the child to be born will be called holy, the Son of God. [Lk 1:35] We also know that, from the very beginning, others, including Elizabeth, Simeon and Anna, were inspired to testify to this relationship. [Lk 1:43; 2:32; and 2:38]. Certainly the angels message to the shepherds made this very clear [Lk 2:11] as did the Star [Mt 2:2,4].
But the most obvious testimony of the Father directly is the theophany after Jesus Baptism: And a voice came from the heavens, saying, “This is my beloved Son, with whom I am well pleased.” [Mt 3:17; Mk 1:9–11; Lk 3:21–22; Jn 1:31–34]. The Father is personally testify personally concerning His son twice more during Jesus public ministry: at the Transfiguration [Mt 17:1–8; Mk 9:2–8; Lk 9:28–36] and before the crowds in John’s theophany [Jn 12:28-30], but at this juncture in Jesus ministry in John’s Gospel, only the Baptismal theophany has occurred.
Thank You, Father, for sharing with us Your Son. And thank You for testifying to the Truth of His mission. We need all the validation we can get, for we are incredulous cynics, having been fooled by things that happened right before our eyes…Thus, believing on the testimony of others is once removed from our experience and is even more difficult to accept. Your testimony is even further removed, having been preserved in Scripture and tradition over 2000 years. No wonder we must totally rely on Your grace to enlighten us: For flesh and blood has not revealed this to you, but my heavenly Father. [Mt 16:17; Mk 8:27–29; Lk 9:18–20]. Grant us Your Spirit that He may fill us with true knowledge and love of You. Help us to be among the Blessed…who have not seen and have believed.[Jn 20:29]
The testimony he gives on my behalf is true. This is what Jesus knows. Again, on what basis does He know this. We might reiterate the ways of His knowing and point out that with His direct Divine Knowledge, He knows that with God, there can be nothing but what “is,” with His Beatific Vision, He knows that the Father is all loving, all knowing, and all true, not just truth. His infused knowledge would have validated everything He knows about the created universe and about uncreated reality. Finally, He would have come to understand that this all made perfect sense, it all fit together without conflict or contradiction, it all was proven, and thus be able to testify on the basis of His observations and conclusions that God’s testimony was true…but this all would be reiteration, ground covered, old territory, rehash. Where to validate the Truth of God’s testimony.
We might follow some of the same avenues of investigation: epistemologically reviewing that, while we cannot verify that what we see, what we witness is true, not because it isn’t but because we cannot be certain that we are completely aware of its reality as it is. We may be myopic, addled, drowsy, distracted, unobservant…or, epistemologically speaking, the reality out there is not what I am considering in here, in my brain. Having said that, through faith we can say that the God who is, who was and who will be, the great “I AM” is, He is Being, Being is His essence. And this is apart from my observing it, understanding it, accepting it, or even knowing about it. God is. And so, to the extent of God’s enabling them to be, is all the rest of creation… it’s all very happy, tootling along in existence, apart from my awareness, apart from even my existence. Amazing and disconcerting as this may be for Type A controllers! Of course, for Type M [for Mary] “unto’ers”, they realize that everything in God’s good universe, everything is within God’s plan, God’s providence, and it is all a great gift, given to each of them; it is continually, comfortably, and lovingly done unto them [and, indeed, each of us whether we accept and enjoy it or not].
Truth is thus separate from and not dependent on my acceptance, understanding or even awareness. And since the same is true of God, since A = C and B = C, A = B, God is both true and Truth. And His testimony on behalf of anything, but in particular, of whom He is best acquainted, His own Word, His own perfect Image, His own Son.
Father, help me to always appreciate Your being true, Your being Truth. I sometimes wander off seeking truth apart from You, not that, in my more lucid moments I don’t realize I cannot find it apart from You…but my mind and heart are clouded by sin and instability, awkwardness and lies and I wander and get lost. Bring me back and teach me Your Truth. Amen. Alleluia!!!
 Scripture texts in this work are taken from the New American Bible, revised edition © 2010, 1991, 1986, 1970 Confraternity of Christian Doctrine, Washington, D.C. and are used by permission of the copyright owner. All Rights Reserved. No part of the New American Bible may be reproduced in any form without permission in writing from the copyright owner.